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ISSN 1748-0221
16:47 - Friday, 14 June 2024
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    JINST Instrumentation Theses Archive

2018 JINST TH 003    

Ph.d. degree
Weizmann Institute of Science, Israel, 2018

Luca Moleri

Supervisor:Shikma Bressler, Amos Breskin

Development of large-area gas-avalanche Resistive-Plate WELL detectors: potential sampling elements for digital hadron calorimetry


  • Micropattern gaseous detectors (THGEM)
  • Calorimeters
  • Performance of High Energy Physics Detectors
  • Detector design and construction technologies and materials


The construction of new accelerators goes along with the development of advanced detectors and instrumentations. Since many scenarios of new physics Beyond the Standard Model (BSM) of particles involve hadronic-decay channels, efforts are made to develop modern calorimetry systems. All experiments designed for future linear colliders foresee the implementation of a (semi-)Digital Hadron Calorimeter ((s)DHCAL) as a key-element for their expected performance.
The present work targeted the development of a large-area, robust, thick detector concept, suitable as sampling element in a sDHCAL and for other applications requiring particle imaging at moderate, sub-mm spatial resolution over a large area.
As a solution, the few-mm thin Resistive-Plate Well (RPWELL) sampling element concept, developed at WIS, was suggested: a single-sided Thick Gas Electron Multiplier (THGEM) electrode coupled to the readout anode through a highly Resistive Plate (RP).
Several detector prototypes, reaching a size of 500 x 500 mm2, were built. They incorporated either Semitron ESD225 acetal, or silicate doped-glass Resistive Plate (RP). Methods were developed for e ectively coupling the RP to the readout anode.
The detector prototypes underwent various systematic investigations - both in the laboratory, and with muon and high-rate pion beams at the European Organization for Nuclear Research (CERN)-Super Proton-Synchrotron (SPS).The presented results allow for a deeper understanding of the RPWELL detector concept and properties. Moreover, they are essential for optimizing the design of future large-area prototypes and their performances for di erent applications. Their main properties are: stable operation with Ne/(5%)CH4, Ar/(5%)CH4 and Ar/(7%)CO2 gas mixtures. High efficiency (>98%) at low average pad multiplicity ( 1.2). Position resolution of 0.28 mm. These properties make the RPWELL a competitive technology, compared to other candidate sampling elements for sDHCAL or Digital Hadron Calorimeter (DHCAL).
Based on this study, the preferable RPWELL detector configuration for future (s)DHCAL would include a 3 mm drift gap, single-sided THGEM electrodes with segmented holes pattern (segmentation similar to that of the readout anode), Semitron ESD225 or doped silicate-glass resistive-plate coupled to the anode through graphite/epoxy.
The preferred operation gas mixture is the non-ammable Ar/(7%)CO2.
Future RPWELL-based (s)DHCAL prototypes will be read out by the (s)DHCALdedicated MICROROC readout electronics - the next step towards the integration of RPWELL sampling elements into a full (s)DHCAL prototype.

for assistance and suggestions: the JINST editorial office